blow molding final compatible

8/12/2019 Blow Molding Final Compatible

1/25

By Garrett Pritchyk,Bryant Richardson, and Mike Scesa


2/25

Polymer process that creates hollow plastic parts This process begins with melting down the

plastic that is to be blow molded in to a parison

Parison - in blow molding, the hollow tube of plastic melt extruded fromthe die head, and expanded within the mold cavity by air pressure toproduce the molded part.

Hot air blown into the parison forces it againstthe mold walls where it is then cooled

Mainly limited to processing of thermoplastics Most plastic bottles are processed this way There are three main types of blow molding


3/25

Process of blow molding originated fromblowing of glass then adapted to polymers

Evidence of Egyptians and Babylonians usingblow molding for plastics

Enoch Ferngren and William Koptike are thepeople credited for the process of blow molding Sold the first blow molding machine to Hartford

Empire Company in 1937

In the United States soft drink industry theamount of plastic containers went from zero in1977 to ten Billion in 1999. (Wikipedia.org)


4/25


5/25

Mass Range 0.005 - 0.3 kg

Range of section thickness 0.4 - 3 mm

Tolerance 0.25 - 1 mm

Roughness 0.2 - 1.6 m

Surface roughness Very Smooth

Medium Tooling Cost (relative)

Medium Equipment Cost (relative) Low Labor Intensity

Batch size can range from 500 - 50,000,000 units


6/25

Extrusion blow molding

Injection blow molding

Stretch blow molding


7/25

Begins with a parison/ pre-form and is thenplaced into an enclosed cooled metal mold

Then air is blown into this mold to shape thematerial to the desired shape

Once it is cooled the part is ejected from themold

Can be made continuously or intermittently


8/25

http://www.petmachine.in/images/pet_extrusion_blow_molding.gif


9/25

Shuttle Machinery

-Used to make large quantities of

product

-Size of mold can range from small

bottles up to 30 liter drums

-Multiple molds and parisons

-Very Important in making

bottles for food storage-Used for making containers

that need up to six layers

-Used for medical containers

-Blowpins are forced into the

molds to calibrate the parts

while forcing air into themolds

Rotary Blow molding


10/25

Reciprocating Screw

Machinery-Uses hydraulic pressure

to blow the mold-Used for making HDPE

dairy containers and five

gallon PC water cooler

containers

-Up to 8-head machines

for output of multiplecontainers

Accumulator Head Machinery

-An internal plunger uses

hydraulic pressure to blowthe mold

-Can make products with up

to 7 different layers of

materials

-Used to make gasonline

containers, playgroundequiptment, and other large

http://www.gefran.com/UserFiles/Image/So

lutions/Marzo_2008/Blow-Molding_eng.jpg


11/25

http://en.wikipedia.org/wiki/Blow_Molding

http://www.packagingmag.com.au/Uploads/PressReleases/p

ack/Images-

20080219/blow.jpg


12/25

Dairy containers (HDPE)Water Cooler Containers (PC)Medical Containers

Gasoline tanksPlayground EquipmentShampoo bottlesPipesHoses Industrial parts and drums


13/25

Polymer melt is supplied to mold halves from injectionmolding machine

Pre-form injection molded over a mandrel and transferredto the blowing die

Air is injected under pressure through the mandrelblowing the polymer against the mold walls where it coolsand freezes as with extrusion blow molding


14/25

Shear & temperature dependent viscosity Temperature-dependent tensile strength on

the pin Tensile elongation during inflation Crystallization kinetics on the core pin Crystallization kinetics during blowing and

cooling


15/25

Gives much bettercontrol over finishedcomponent weight and

wall thickness thanextrusion blow-molding

better precision in the

unblown, injection molded

neck areas, lending itselfto screw closures, etc.

Solid handles can bemolded in

http://www.global-b2b network.com/direct/dbimage/50069572/Injection_Blow_Molding_Machine_MSZ25.jpg


16/25

Injection molded preformed top IR heaters raise the pre-form above the glass

transition temperature Core rod stretches polymer to the bottom of

the mold High pressure air expands the polymer to the

walls of the mold


17/25

Single stage

Pre-form and blow molding process happen in the

same machine Convent for small batch production

Two stage

Pre-form is made in one machine

Blow molding occurs in another

Faster production for large batches


18/25

Low tool and die cost Fast production rate

Molds complex parts Stretching results in strain hardening Reduces product weight by 10% when

compared to similar methods Limited to hollow parts Wall thickness is hard to control


19/25

http://www.germes-online.com/direct/dbimage/50030644/Stretch_Blow_Molding_Machine.jpg


20/25

http://www.riken.go.jp/lab-www/mat-fab/blow/netpictures/petbottle/PET%20process.jpg


21/25

Lear Corp. & Fremont Plastic Molds

Ribbed parts are formed using specialized core

rod with ribs Increases friction for non-slip covers

Bayer Polymers

Flexible thermoplastics are blow molded over

metallic inserts in the die

Creates a hard and soft layer

Hybrid seats and cross-beams


22/25

http://www.ptonline.com/dp/zones/ptzones/index.cfm?cat=BLM01&zone=BLM


23/25

Thermoplastics PET

PC

HDPE

LDPE

PP

ABS

some PVC

Limited levels of reinforcement for compositematerials Thickness should be as uniform as possible to avoid

distortion


24/25

CES EduPack 2008 software, Granta Design Limited,Cambridge, UK, 2008.

www.blowmachines.com

www.wikipedia.org www.riken.go.jp/lab-www/mat-fab/blow/


25/25

blow molding final compatible

Documents